Embodiments of the invention relate to an image sensor and a method of fabricating the same.
Generally, in a complementary metal-oxide semiconductor (CMOS) image sensor, a micro-lens is formed on an uppermost layer. Light collected by the micro-lens passes through a color filter array layer and a planarization layer and is converted into an electric signal by a light reception unit such as a photodiode.
The image sensor displays an image using the converted electric signal. At this point, a focal-length of the micro-lens, a size and distribution of the color filter, a thickness of a Planarization layer, and a pitch size of the photodiode should be determined considering relative relations therebetween.
Meanwhile, the focal length of the micro-lens may vary greatly. Further, it is difficult to standardize the focal length of the micro-lens. That is, since a basic pattern is formed on a lens forming photosensitive layer through a defocus of a scanner, and the micro-lens is generally fabricated by performing a thermal reflow process on such a photosensitive layer, the focal length may vary greatly and the standardization of the focal length is difficult. Therefore, reproducibility of the micro-lens shape within certain manufacturing tolerances may be challenging.